US4847570A - Electronic, contactless switchgear - Google Patents

Electronic, contactless switchgear Download PDF

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Publication number
US4847570A
US4847570A US07/114,935 US11493587A US4847570A US 4847570 A US4847570 A US 4847570A US 11493587 A US11493587 A US 11493587A US 4847570 A US4847570 A US 4847570A
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US
United States
Prior art keywords
switchgear according
coils
oscillator
electronic
electronic switchgear
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
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US07/114,935
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English (en)
Inventor
Peter Schramm
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IFM Electronic GmbH
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IFM Electronic GmbH
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Publication date
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Assigned to I F M ELECTRONIC GMBH reassignment I F M ELECTRONIC GMBH ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SCHRAMM, PETER
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/95—Proximity switches using a magnetic detector
    • H03K17/952—Proximity switches using a magnetic detector using inductive coils
    • H03K17/953—Proximity switches using a magnetic detector using inductive coils forming part of an oscillator
    • H03K17/9535—Proximity switches using a magnetic detector using inductive coils forming part of an oscillator with variable amplitude

Definitions

  • the invention relates to electronic, contactless switchgear, having an externally modulatable component, preferably an externally modulatable coil, a switch amplifier connected to the output side of the component or coil, and an electronic switch, for instance a transistor, a thyristor or a triac, that is controllable by the component or the coil.
  • an externally modulatable component preferably an externally modulatable coil
  • a switch amplifier connected to the output side of the component or coil
  • an electronic switch for instance a transistor, a thyristor or a triac, that is controllable by the component or the coil.
  • an externally modulatable component is part of the electronic switchgear in question.
  • the component may be any one of quite various kinds of externally modulatable components.
  • the invention relates to electronic switchgear of the above-described type, in which the externally modulatable component is embodied as a coil, and the coil is part of the circuit of an externally modulatable oscillator having an oscillator amplifier and a feedback.
  • switchgear embodied as a closing element
  • the initially non-conducting electronic switch now becomes conductive
  • switchgear embodied as an opener the initially conductive electronic switch is now made to block.
  • an indication can also be provided as to whether a physical variable of a modulating medium to which the switchgear is sensitive has attained a corresponding value.
  • switchgear of the above-described type is the externally modulatable oscillator, which is typically embodied such that it can be inductively modulated; in this case it is an inductive proximity switch.
  • the damping that is present when a metal part has not approached must be as low as possible, so that upon the approach of the metal part toward the inductive proximity switch, damping caused by eddy currents can be evaluated.
  • the conventional inductive proximity switches are not readily as sensitive as would be desired.
  • the conventional inductive proximity switches must not be surrounded on all sides by metal, and such inductive proximity switches cannot detect ferromagnetic modulating elements through damping paramagnetic material, for instance through aluminum housing walls.
  • the conventional inductive proximity switches respond to modulating elements both of paramagnetic and of ferromagnetic material.
  • the electronic contactless switchgear according to the invention is characterized initially and substantially in that a second externally modulatable coil is provided, the two coils are connected in series in opposite directions, and the junction point of the two coils is connected to the input of the switch amplifier, either directly or indirectly.
  • a substantial factor in the teaching of the invention is that in accordance with the invention two externally modulatable coils are provided, that the two coils are modulated differently, even if only slightly differently, and that because the two coils are connected in series in opposite directions, a differential signal is obtained, which can be particularly well evaluated, so that the electronic, contactless switchgear according to the invention is particularly sensitive and in a special way.
  • the teaching of the invention is particularly applicable in electronic, contactless switchgear of the type in question, in which the coil is part of the circuit of an externally modulatable oscillator having an oscillator amplifier and a feedback. Then the teaching of the invention comprises providing the series circuit of the two coils as a feedback or - in addition to a feedback realized in another manner - as a second feedback, and disposing it in the outlet circuit of the oscillator amplifier and connecting the junction point of the two coils with the input of the oscillator amplifier.
  • the electronic contactless switchgear according to the invention can be sensitive in qualitatively different ways.
  • the dissimilar modulation of the magnetic circuits of the two coils is evaluated; this embodiment is capable of detecting ferromagnetic modulating elements through paramagnetic material.
  • the dissimilar damping of the two coils is evaluated; this embodiment can be designed such that it responds only to modulating elements made of paramagnetic material.
  • the teaching of the invention includes various embodiments, on the one hand embodiments in which the differential signal of the two coils is evaluated differently from the manner in the context of an oscillator, and on the other hand embodiments in which the differential signal of the two coils is obtained by means of dissimilar damping of the two coils.
  • the teaching of the invention as well as embodiments and further refinements of the teaching of the invention will be described in further detail referring to an exemplary embodiment shown in the drawing, in which the differential signal of the two coils is evaluated in the context of an oscillator, this differential signal being obtained by modulation of the magnetic circuit of the two coils.
  • FIG. 1 is a block circuit diagram of electronic, contactless switchgear in accordance with the invention
  • FIG. 2 is a circuit diagram of a preferred embodiment of an oscillator of the electronic, contactless switchgear of FIG. 1;
  • FIG. 3 is a preferred embodiment of the two coils belonging to the oscillator of FIG. 2.
  • the electronic switchgear 1 shown in FIG. 1 with the aid of a block circuit diagram operates in a contactless manner; that is, it responds to an approaching ferromagnetic modulating element, not shown, and is connected via an outer lead 2 to one pole 3 of an operating voltage source 4 and via only one further outer lead 5 to a connection 6 of a consumer 7, while the other connection 8 of the consumer 7 is connected to the other pole 9 of the source of operating voltage 4.
  • the switchgear 1 shown is connected in a known manner via a total of only two outer leads 2, 5 to the operating voltage source 4, on the one hand, and the consumer 7, on the other.
  • the switchgear 1 shown in its basic structure, comprises an externally modulatable oscillator 10, a switch amplifier 11 connected to the output side of the oscillator 10, an electronic switch 12, for instance a transistor, a thyristor or a triac, which is controllable by the oscillator 10 via the switch amplifier 11, and a supply circuit 13 representing the supply voltage for the oscillator 10 and the switch amplifier 11.
  • a rectifier bridge 14 is also provided, because in the exemplary embodiment the operating voltage source 4 is a source of alternating voltage.
  • FIG. 2 now shows that the oscillator 10 first has an oscillator amplifier 15 and a feedback 16, and that a second feedback 17 is provided, and a second feedback 17 has two externally modulatable coils 18, 19 connected in series in opposite directions.
  • the series circuit of the coils 18, 19 is located in the output circuit of the oscillator amplifier 15, and the junction point 20 of the two coils 18, 19 is connected to the input 21 of the oscillator amplifier 15.
  • the magnetic circuits of the two coils 18, 19 are modulated, in fact are modulated to different extents. This is also true even when, as in the exemplary embodiment shown, the two coils 18, 19 are located in a magnetic circuit that is substantially common to both coils 18, 19. In the exemplary embodiment shown, as in FIG. 3, this is accomplished by providing that a common iron core 22 is associated with both coils 18, 19.
  • the iron core 22 is E-shaped in cross-section, namely cup-shaped, and the two coils 18, 19 are disposed one after the other in the modulation direction, that is, in the axial direction of the cup-shaped iron core 22.
  • the distance of the coil 18 from the bottom 23 of the iron core 22, the distance of the coil 19 from the bottom 23 of the iron core 22, the distance between the two coils 18 and 19, the diameter D of the iron core 22 and the height of the iron core 22 are parameters with the aid of which the sensitivity of the electronic switchgear 1 according to the invention can be modulated.
  • one of average skill in the art can empirically ascertain the other parameters in order to optimize the sensitivity of the electronic switchgear according to the invention.
  • the electronic switchgear it is basically possible to connect the second feedback 17 in the manner of a positive feedback. What is shown in the drawings, however, is an exemplary embodiment in which the second feedback 17 is connected in the manner of a negative feedback.
  • the oscillator amplifier 15 is embodied as frequency-selective, as shown in FIG. 2, namely being provided with an RC element 24 as the frequency-determining circuit portion.
  • the oscillator amplifier 15 has an input transistor 25; an emitter resistor 26 is located in the emitter circuit of the input transistor 25, and the junction point 20 of the coils 18, 19 is connected to the emitter 27 of the input transistor 25; and the RC element 24 is connected to the collector 28 and to the base 29 of the input transistor 25.
  • the oscillator amplifier 15 has an output transistor 30, and the series circuit comprising an emitter resistor 31 and the two coils 18, 19 is located in the emitter circuit of the output transistor 30.
  • FIG. 2 also shows a preferred exemplary embodiment in the sense that a coupling capacitor 33 is provided between the collector 28 of the input transistor 25 and the base 32 of the output transistor 30, and that a feedback resistor is connected, as the feedback 16, between the collector 34 of the output transistor 30 and the end of the coupling capacitor 33 remote from the collector 28 of the input transistor 25.

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  • Electronic Switches (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
US07/114,935 1986-10-30 1987-10-30 Electronic, contactless switchgear Expired - Fee Related US4847570A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE3637028 1986-10-30
DE3637028 1986-10-30
DE3638409 1986-11-11
DE3638409 1986-11-11

Publications (1)

Publication Number Publication Date
US4847570A true US4847570A (en) 1989-07-11

Family

ID=25848918

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/114,935 Expired - Fee Related US4847570A (en) 1986-10-30 1987-10-30 Electronic, contactless switchgear

Country Status (3)

Country Link
US (1) US4847570A (de)
EP (1) EP0265844B1 (de)
DE (2) DE3772515D1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6272001B1 (en) * 1997-02-14 2001-08-07 The Nippon Signal Co., Ltd. Emergency stop switch and emergency stop switch circuit

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3027242B2 (ja) * 1990-10-04 2000-03-27 ヴェルナー トゥルク ゲゼルシャフト ミット ベシュレンクテル ハフツング ウント コンパニー コマンディトゲゼルシャフト 誘導近接スイッチ
DE4032001A1 (de) * 1990-10-09 1992-05-27 Ifm Electronic Gmbh Induktiver naeherungsschalter
DE4313084C2 (de) * 1993-04-21 1995-11-23 Ifm Electronic Gmbh Induktiver Näherungsschalter
DE10125278C2 (de) * 2001-05-23 2003-04-10 Cherry Gmbh Induktive Positionsschaltvorrichtung
DE10242385B4 (de) 2002-09-12 2005-09-01 Cherry Gmbh Induktive Sensoreinheit
DE10341485B4 (de) * 2003-09-05 2005-08-25 Casco Schoeller Gmbh Vorrichtung zur Erfassung der Position eines ersten Fahrzeugteils in bezug auf ein zweites Fahrzeugteil, insbesondere zur Bestimmung der Nickposition eines Fahrzeuges und Fahrzeug mit einer derartigen Vorrichtung
US7701201B2 (en) 2003-09-11 2010-04-20 Cherry Gmbh Inductive switch
US7719263B2 (en) 2006-11-22 2010-05-18 Zf Friedrichshafen Ag Inductive position measuring device or goniometer
DE102007026512B4 (de) 2007-06-08 2015-08-13 Ifm Electronic Gmbh Berührungslos arbeitendes Schaltgerät und Verfahren zum Betreiben desselben

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4638262A (en) * 1984-03-09 1987-01-20 Omron Tateisi Electronics Co. Proximity switch with improved response time and antimagnetic field circuitry

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH488279A (de) * 1969-07-25 1970-03-31 Landis & Gyr Ag Induktive Annäherungsschalteinrichtung, insbesondere zur Verwendung als Endschalter
DE2461169C3 (de) * 1974-12-23 1982-07-15 Honeywell Gmbh, 6000 Frankfurt Elektronischer Näherungsschalter
DE2704622A1 (de) * 1977-02-04 1978-08-10 Honeywell Gmbh Wechselstrom-naeherungsschalter
US4513257A (en) * 1981-12-03 1985-04-23 Omron Tateisi Electronics Co. Proximity switch with oppositely polarized coils
DE3220111C1 (de) * 1982-05-28 1983-06-09 Honeywell Gmbh, 6050 Offenbach Überwachungseinrichtung für Näherungsschalter
DE3312756A1 (de) * 1983-04-09 1984-10-11 Pepperl & Fuchs Gmbh & Co Kg, 6800 Mannheim Annaeherungsschalter
DE3513403A1 (de) * 1985-04-15 1986-10-30 Wolf-Jürgen Prof. Dr. 6701 Fußgönheim Becker Verfahren zur reduzierung des temperaturverhaltens eines schwingkreises und nach diesem verfahren kompensierter oszillator
FR2582411B1 (fr) * 1985-05-22 1987-08-21 Petercem Sa Detecteur differentiel a fonctionnement verifiable quelle que soit la position de la cible

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4638262A (en) * 1984-03-09 1987-01-20 Omron Tateisi Electronics Co. Proximity switch with improved response time and antimagnetic field circuitry

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6272001B1 (en) * 1997-02-14 2001-08-07 The Nippon Signal Co., Ltd. Emergency stop switch and emergency stop switch circuit

Also Published As

Publication number Publication date
EP0265844A2 (de) 1988-05-04
DE3735694C2 (de) 1989-04-06
DE3735694A1 (de) 1988-05-11
EP0265844A3 (en) 1989-03-15
DE3772515D1 (de) 1991-10-02
EP0265844B1 (de) 1991-08-28

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Owner name: I F M ELECTRONIC GMBH, TEICHSTRASSE 4, 4300 ESSEN

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Effective date: 19970716

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